libstdc++
sstream.tcc
1 // String based streams -*- C++ -*-
2 
3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
4 // 2006, 2007, 2009
5 // Free Software Foundation, Inc.
6 //
7 // This file is part of the GNU ISO C++ Library. This library is free
8 // software; you can redistribute it and/or modify it under the
9 // terms of the GNU General Public License as published by the
10 // Free Software Foundation; either version 3, or (at your option)
11 // any later version.
12 
13 // This library is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
17 
18 // Under Section 7 of GPL version 3, you are granted additional
19 // permissions described in the GCC Runtime Library Exception, version
20 // 3.1, as published by the Free Software Foundation.
21 
22 // You should have received a copy of the GNU General Public License and
23 // a copy of the GCC Runtime Library Exception along with this program;
24 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
25 // <http://www.gnu.org/licenses/>.
26 
27 /** @file sstream.tcc
28  * This is an internal header file, included by other library headers.
29  * You should not attempt to use it directly.
30  */
31 
32 //
33 // ISO C++ 14882: 27.7 String-based streams
34 //
35 
36 #ifndef _SSTREAM_TCC
37 #define _SSTREAM_TCC 1
38 
39 #pragma GCC system_header
40 
41 _GLIBCXX_BEGIN_NAMESPACE(std)
42 
43  template <class _CharT, class _Traits, class _Alloc>
44  typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
45  basic_stringbuf<_CharT, _Traits, _Alloc>::
46  pbackfail(int_type __c)
47  {
48  int_type __ret = traits_type::eof();
49  if (this->eback() < this->gptr())
50  {
51  // Try to put back __c into input sequence in one of three ways.
52  // Order these tests done in is unspecified by the standard.
53  const bool __testeof = traits_type::eq_int_type(__c, __ret);
54  if (!__testeof)
55  {
56  const bool __testeq = traits_type::eq(traits_type::
57  to_char_type(__c),
58  this->gptr()[-1]);
59  const bool __testout = this->_M_mode & ios_base::out;
60  if (__testeq || __testout)
61  {
62  this->gbump(-1);
63  if (!__testeq)
64  *this->gptr() = traits_type::to_char_type(__c);
65  __ret = __c;
66  }
67  }
68  else
69  {
70  this->gbump(-1);
71  __ret = traits_type::not_eof(__c);
72  }
73  }
74  return __ret;
75  }
76 
77  template <class _CharT, class _Traits, class _Alloc>
78  typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
79  basic_stringbuf<_CharT, _Traits, _Alloc>::
80  overflow(int_type __c)
81  {
82  const bool __testout = this->_M_mode & ios_base::out;
83  if (__builtin_expect(!__testout, false))
84  return traits_type::eof();
85 
86  const bool __testeof = traits_type::eq_int_type(__c, traits_type::eof());
87  if (__builtin_expect(__testeof, false))
88  return traits_type::not_eof(__c);
89 
90  const __size_type __capacity = _M_string.capacity();
91  const __size_type __max_size = _M_string.max_size();
92  const bool __testput = this->pptr() < this->epptr();
93  if (__builtin_expect(!__testput && __capacity == __max_size, false))
94  return traits_type::eof();
95 
96  // Try to append __c into output sequence in one of two ways.
97  // Order these tests done in is unspecified by the standard.
98  const char_type __conv = traits_type::to_char_type(__c);
99  if (!__testput)
100  {
101  // NB: Start ostringstream buffers at 512 chars. This is an
102  // experimental value (pronounced "arbitrary" in some of the
103  // hipper English-speaking countries), and can be changed to
104  // suit particular needs.
105  //
106  // _GLIBCXX_RESOLVE_LIB_DEFECTS
107  // 169. Bad efficiency of overflow() mandated
108  // 432. stringbuf::overflow() makes only one write position
109  // available
110  const __size_type __opt_len = std::max(__size_type(2 * __capacity),
111  __size_type(512));
112  const __size_type __len = std::min(__opt_len, __max_size);
113  __string_type __tmp;
114  __tmp.reserve(__len);
115  if (this->pbase())
116  __tmp.assign(this->pbase(), this->epptr() - this->pbase());
117  __tmp.push_back(__conv);
118  _M_string.swap(__tmp);
119  _M_sync(const_cast<char_type*>(_M_string.data()),
120  this->gptr() - this->eback(), this->pptr() - this->pbase());
121  }
122  else
123  *this->pptr() = __conv;
124  this->pbump(1);
125  return __c;
126  }
127 
128  template <class _CharT, class _Traits, class _Alloc>
129  typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
130  basic_stringbuf<_CharT, _Traits, _Alloc>::
131  underflow()
132  {
133  int_type __ret = traits_type::eof();
134  const bool __testin = this->_M_mode & ios_base::in;
135  if (__testin)
136  {
137  // Update egptr() to match the actual string end.
138  _M_update_egptr();
139 
140  if (this->gptr() < this->egptr())
141  __ret = traits_type::to_int_type(*this->gptr());
142  }
143  return __ret;
144  }
145 
146  template <class _CharT, class _Traits, class _Alloc>
147  typename basic_stringbuf<_CharT, _Traits, _Alloc>::pos_type
148  basic_stringbuf<_CharT, _Traits, _Alloc>::
149  seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __mode)
150  {
151  pos_type __ret = pos_type(off_type(-1));
152  bool __testin = (ios_base::in & this->_M_mode & __mode) != 0;
153  bool __testout = (ios_base::out & this->_M_mode & __mode) != 0;
154  const bool __testboth = __testin && __testout && __way != ios_base::cur;
155  __testin &= !(__mode & ios_base::out);
156  __testout &= !(__mode & ios_base::in);
157 
158  // _GLIBCXX_RESOLVE_LIB_DEFECTS
159  // 453. basic_stringbuf::seekoff need not always fail for an empty stream.
160  const char_type* __beg = __testin ? this->eback() : this->pbase();
161  if ((__beg || !__off) && (__testin || __testout || __testboth))
162  {
163  _M_update_egptr();
164 
165  off_type __newoffi = __off;
166  off_type __newoffo = __newoffi;
167  if (__way == ios_base::cur)
168  {
169  __newoffi += this->gptr() - __beg;
170  __newoffo += this->pptr() - __beg;
171  }
172  else if (__way == ios_base::end)
173  __newoffo = __newoffi += this->egptr() - __beg;
174 
175  if ((__testin || __testboth)
176  && __newoffi >= 0
177  && this->egptr() - __beg >= __newoffi)
178  {
179  this->gbump((__beg + __newoffi) - this->gptr());
180  __ret = pos_type(__newoffi);
181  }
182  if ((__testout || __testboth)
183  && __newoffo >= 0
184  && this->egptr() - __beg >= __newoffo)
185  {
186  this->pbump((__beg + __newoffo) - this->pptr());
187  __ret = pos_type(__newoffo);
188  }
189  }
190  return __ret;
191  }
192 
193  template <class _CharT, class _Traits, class _Alloc>
194  typename basic_stringbuf<_CharT, _Traits, _Alloc>::pos_type
195  basic_stringbuf<_CharT, _Traits, _Alloc>::
196  seekpos(pos_type __sp, ios_base::openmode __mode)
197  {
198  pos_type __ret = pos_type(off_type(-1));
199  const bool __testin = (ios_base::in & this->_M_mode & __mode) != 0;
200  const bool __testout = (ios_base::out & this->_M_mode & __mode) != 0;
201 
202  const char_type* __beg = __testin ? this->eback() : this->pbase();
203  if ((__beg || !off_type(__sp)) && (__testin || __testout))
204  {
205  _M_update_egptr();
206 
207  const off_type __pos(__sp);
208  const bool __testpos = (0 <= __pos
209  && __pos <= this->egptr() - __beg);
210  if (__testpos)
211  {
212  if (__testin)
213  this->gbump((__beg + __pos) - this->gptr());
214  if (__testout)
215  this->pbump((__beg + __pos) - this->pptr());
216  __ret = __sp;
217  }
218  }
219  return __ret;
220  }
221 
222  template <class _CharT, class _Traits, class _Alloc>
223  void
224  basic_stringbuf<_CharT, _Traits, _Alloc>::
225  _M_sync(char_type* __base, __size_type __i, __size_type __o)
226  {
227  const bool __testin = _M_mode & ios_base::in;
228  const bool __testout = _M_mode & ios_base::out;
229  char_type* __endg = __base + _M_string.size();
230  char_type* __endp = __base + _M_string.capacity();
231 
232  if (__base != _M_string.data())
233  {
234  // setbuf: __i == size of buffer area (_M_string.size() == 0).
235  __endg += __i;
236  __i = 0;
237  __endp = __endg;
238  }
239 
240  if (__testin)
241  this->setg(__base, __base + __i, __endg);
242  if (__testout)
243  {
244  this->setp(__base, __endp);
245  this->pbump(__o);
246  // egptr() always tracks the string end. When !__testin,
247  // for the correct functioning of the streambuf inlines
248  // the other get area pointers are identical.
249  if (!__testin)
250  this->setg(__endg, __endg, __endg);
251  }
252  }
253 
254  // Inhibit implicit instantiations for required instantiations,
255  // which are defined via explicit instantiations elsewhere.
256  // NB: This syntax is a GNU extension.
257 #if _GLIBCXX_EXTERN_TEMPLATE
258  extern template class basic_stringbuf<char>;
259  extern template class basic_istringstream<char>;
260  extern template class basic_ostringstream<char>;
261  extern template class basic_stringstream<char>;
262 
263 #ifdef _GLIBCXX_USE_WCHAR_T
264  extern template class basic_stringbuf<wchar_t>;
265  extern template class basic_istringstream<wchar_t>;
266  extern template class basic_ostringstream<wchar_t>;
267  extern template class basic_stringstream<wchar_t>;
268 #endif
269 #endif
270 
271 _GLIBCXX_END_NAMESPACE
272 
273 #endif